Chicago Regulation Change Provides Opportunity for Phius Professionals

Al Mitchell

Al Mitchell

Phius Technical Staff Member Al Mitchell wrote this week’s blog post, which discusses the recent change in regulations related to coach houses in Chicago, and how designing these new buildings to Phius standards is a win-win for all parties.

The City of Chicago has lifted a nearly half-century ban on accessory dwelling units (ADUs), opening up a door for some people to build additional units on their property. The pilot program for ADU construction pertains to rentable units, occupiable by relatives, tenants, or even to be used as additional space from the primary home. There are two types of ADUs acknowledged by this regulation: a detached dwelling unit, such as a coach house or apartment on top of the garage, or a conversion unit, such as a built-out attic or basement.

However, there are a handful of caveats to consider. First, the allowances for ADUs, whether coach houses or conversion units, are limited to select pilot zones. There are five pilot zones: North, Northwest, West, South, and Southeast. These zones cover portions of 25 of the 77 Chicago community areas. Each area has a few special requirements for different types of ADU. For example, the North and Northwest zones can have a coach house built on the property before a primary house is built, while the other three zones require a primary house to be built on the lot before a coach house can be built. In the West, South, and Southwest zones, buildings must be owner-occupied in order to add a conversion unit. All ADUs in Chicago are to be rented for a minimum period of 1 month, and there is a requirement for a certain number of affordable units on larger properties where more units can be added.

 

Blog Pic 1This offers a great opportunity for people to add value to their property, create flexible living spaces (especially to take advantage of the benefits of multi-generational housing) or build a unit that can provide additional income for the owner while providing right-sized, cost-effective housing for another person. Approximately 70% of the lots in Chicago are 25 feet wide and face broadside south, making the applicability of this format broad. The aim of this blog is to make the case for building these newly allowed accessory dwelling units following the Phius passive building standards to create comfortable spaces, save energy and operational costs, and provide spaces that can weather inclement weather conditions, especially during a failure of space conditioning.

Analysis

Conversion units like the ones proposed in Chicago, would likely require a complete building retrofit to achieve the maximum cost and energy saving potential. This study is going to focus on detached coach houses, of maximum permitted dimensions. This comes at an apt time for Phius, as 2021 has marked the release of a user-friendly and streamlined prescriptive compliance path, as well as the performance target curves have been reworked to include allowances for small living spaces (in response to the tiny home craze).

Looking at coach house potentials, four cases were selected for evaluation. Three of the cases represent a single-story unit, one in the place of the garage, one pushed forward with open parking on the alley, and one built on top of the garage. The fourth case is a two-story coach house with no garage. The smaller units are studios, with no bedroom considered, one occupant, and the two-story coach house has one bedroom and two occupants. The standard kit of appliances is a dishwasher, refrigerator, and an induction range. Electric resistance water heaters are used in the base cases and a split heat pump system provides space conditioning.

The base cases follow code minimum constructions and windows per IECC 2018.  An envelope airtightness of 0.31 CFM50/sqft was used to match typical construction. The Phius CORE Prescriptive Path follows the prescriptive requirements per Chicago – Midway airport, and uses the default airtightness of 0.04 CFM50/sqft. The prescriptive path windows are whole window U-Values, and are set based on the required prescriptive comfort standards. Per the water heater efficiency requirements, the water heater was upgraded to a small heat pump water heater. The performance path uses 0.06 CFM50/sqft as the required airtightness metric, and follows the same window set as the prescriptive path. A heat pump water heater was used.  The other opaque assemblies were backed off from the conservative prescriptive path to meet the required calculated targets. Please reference the table below for the envelope performance specs in the study.

 

Case Wall R Roof R Slab R Window-U Airtightness CFM50/sf
IECC 2018 18.4 44.0 10.6 0.3 0.31
Phius 2021 CORE Prescriptive 40.0 71.0 21.6 0.16 0.04
Phius 2021 CORE 26.8 52.0 17.2 0.16 0.06
Blog Pic 2

 

Conclusion

The cases designed to Phius standards prove to reduce the space conditioning loads significantly, as shown in the Space Conditioning Results Chart. These outputs are specific per area, making it easy to compare different building sizes. Per the Source Energy Chart, the Prescriptive and Performance averages save 35% and 30% respectively. These source energy savings directly reflect the anticipated savings on an electrical power bill for the tenant of these coach houses.

Coach houses built to these passive building guidelines project significant energy savings that will directly benefit the occupants of these buildings, on top of the other comfort and passive survivability (what happens during a power failure – stay tuned for a part two blog). The required upgrades to meet the performance path is principally based around better windows and airtightness, saving on other insulation requirements per the prescriptive path. 

Blog Pic 3

10th Annual NAPHC – best party of the year, maybe ever…

Wow – was that a successful conference! It has been a week and I am still processing it all. Chicago was unlike any other conference — things did not slow down in the office after it was all over, they rather accelerated. It indeed appears we have reached a tipping point.

From more than one person I heard that it seemed that the quality of work, detailing expertise and technical knowledge, size of projects and complexity of building types had reached a new high. And, compared to the early years, we were not just talking theory and intentions—but what people had done! Really impressive.

LEFT: Dr. Hartwig Künzel giving the Day 2 Keynote -- RIGHT: Sebastian Moreno-Vacca participating in the Architects' Hootenanny (L-R: T.McDonlad, T.Smith, J.Moskovitz, Sebastian, ?)

LEFT: Dr. Hartwig Künzel giving the Day 2 Keynote — RIGHT: Sebastian Moreno-Vacca participating in the Architects’ Hootenanny including (l-r): T.McDonald, T.Smith, J.Moskovitz, Sebastian, C.Hawbecker)

New modeling tools such as WUFI Passive (Technical keynote Hartwig Künzel, day two) are making building science interrelationships more visible and intuitively understandable. WUFI Passive is enabling CPHCs to optimize designs using “hygrothermal mass” (ever heard of that?) to optimize humidity loads and even to inform design decisions overall (as Sebastian Moreno-Vacca illustrated in his session) to create a unique architectural language! How cool is that! Science, heat fluxes and thermal dynamics begin to shape architectural form.

Dirk Lohan, Principal, Lohan Anderson -- Welcomes conference attendees to Chicago

Dirk Lohan, Principal, Lohan Anderson — Welcomes conference attendees to Chicago

Dirk Lohan—Mies Vander Rohe’s grandson, and an extremely accomplished architect in his own right—hinted at this development during his welcoming remarks.

“I believe that we will begin to see as beautiful what also is energy-conscious,” said Lohan.

Supported by the John D. and Catherine T. MacArthur Foundation

But maybe the most significant news is the explosive development in the multifamily affordable housing sector. It is seeing significant growth, interest and pilot developments going up in many places of the country. Thanks to the support from the John D. and Catherine T. MacArthur Foundation, we were able to make this our core topic for the conference and will be able to actively provide support to the affordable development community.

The pre-conference sessions included a daylong affordable housing Hootenanny that brought together successful affordable, multifamily housing project teams together who generously shared lessons learned and experience. Four different project teams presented during an intense full day. The morning and afternoon presentations drew full rooms of affordable housing developers who soaked up the information and had terrific, incisive questions

The same teams presented again during the core conference breakouts in a more condensed form for those who were unable to attend the hootenanny. In addition, there were more presentations on even bigger size affordable projects in progress:

  • A 101 unit affordable development in New York now under construction in the Rockaways (Steve Bluestone, Bluestone Org.)
  • A planned affordable retrofit of a 24 story historical brick building in Chicago (Doug Farr, Tony Holub from Farr and Assoc.), the Lawson House.
  • 24 story residence hall under construction in NYC (Matt Herman, BuroHappold)
L-R: Steve Bluestone presenting with Lisa White, Doug Farr, Matthew Herman

L-R: Steve Bluestone presenting with Lisa White, Doug Farr, Matthew Herman

Really amazing stuff.

Katherine Swenson

Katherine Swenson, Vice President, National Design Initiatives for Enterprise Community Partners — Day 1 Opening Keynote

Of course this growth has been fueled by forward-looking programs that recognize that energy efficient homes make so much sense for affordable housing developers/owners and dwellers. Katie Swenson from the Enterprise Foundation was a breath of fresh air–dynamic, positive, and motivating opening keynote. She explained that in her and her organization’s eyes energy is a critical part in assuring not just housing for people—but healthy housing! “Health is the new green,” she said, and of course passive housing delivers here with excellent comfort, indoor air quality and the added bonus of resiliency when the power goes out. Katie announced that the Green Communities criteria had just included PHIUS+ 2015 certification as one of the highest energy point options.

Other affordable housing agencies also have made a move: the Pennsylvania Housing Finance Agency (PHFA) awarded bonus points in its last round of selecting projects for Low Income Housing Tax Credits. More recently the New York State Homes & Community Renewal (HCR) effort was mentioned in a release regarding energy efficiency measures from the White House. Those agencies now directly encourage passive building standards in their RFPs. Remarkable!

Sam Rashkin, U.S. D.O.E. -- Closing Plenary Keynote

Sam Rashkin, U.S. D.O.E. — Closing Plenary Keynote

On the other coast. Seattle just amended their multifamily building code to allow additional floor area ration (FAR) for projects that meet the PHIUS+ 2015 criteria. That’s a significant incentive for developers.

Things are cookin’!

The core conference, as usual, was chock full of goodness. There were examples of how the new PHIUS+ 2015 climate specific passive building standards helped to optimize costs both here in North America (presentations by Chicago’s Tom Bassett-Dilley, Dan Whitmore, and) and internationally (Günther Gantolier from Italy). There were nuts-and-bolts presentations on wall assembly solutions (Tom Bassett-Dilley again), air and water barrier best practices (Marcus and Keith). And, the Builders Hootenanny—led by Hammer & Hand’s Sam Hagerman, focused on component challenges such as sourcing airtight FDA approved doors for commercial construction.

The U.S. DOE’s Sam Rashkin closed the conference with an unexpected message: he suggested that we needed to rename a few things to facilitate behavioral change. He posited that ZERH, LEED, PHIUS and other green building programs are essentially fossil fuel use rehab centers trying to rehabilitate an addicted nation and to show how it can be done differently. He received a standing ovation.

A few more comments on pre-conference workshops – three WUFI Passive classes drew almost 80 people and they all were super happy throughout the two days! Who would have thought! Happy people energy modeling!

LEFT: Marc Rosenbaum's lecture on Renewables -- RIGHT: Joe Lstiburek on Multifamily Building Science & HVAC

LEFT: Marc Rosenbaum’s lecture on Renewables — RIGHT: Joe Lstiburek on Multifamily Building Science & HVAC

Marc Rosenbaum single-handedly won first place in registering the most people for his class to connect passive principles with renewables to get to positive energy buildings (the logical next step).

Joe Lstiburek placed a close second (sorry Joe) and did a phenomenal job in covering ventilation concerns in large multifamily buildings. Rachel Wagner showed the most awesome cold climate details that I have ever seen. Galen Staengl took folks on a spin to design multifamily and commercial mechanical systems.

And Gary Klein topped it all off by reminding us that without efficient hot water systems design in multifamily, no cigar!

Thanks to all presenters and keynotes! You made this an excellent and memorable event.

I have not even mentioned the first North American Passive Building Project Awards—the entries were just beautiful projects—check out the winners here. I must mention the overall Best Project winner of 2015, as I believe this is pivotal: Orchards at Orenco. What a beautiful project, the largest fully certified PHIUS+ project in the country to date, a game-changer, underlining affordable multifamily projects on the rise.

I’m extremely happy that the Best Projects winners for young CPHC/architects was a tie, and both winners are women! Congrats to Barbara Gehrung and Tessa Smith! Go girls, you are the next generation of leaders!

L-R: Best Overall Project: Orchards at Orenco; Best Project by CPHC under 35 (tie): Island Passive House, Tessa Smith; Best Project by CPHC under 35 (tie): ECOMod South, Barbara Gehrung

L-R: Best Overall Project: Orchards at Orenco; Best Project by CPHC under 35 (tie): Island Passive House, Tessa Smith; Best Project by CPHC under 35 (tie): ECOMod South, Barbara Gehrung

One last note on a thing: Passive building people know how to party while devouring the most challenging, inspiring energy science, details, philosophies (Jevons paradox – Zack Semke’s fascinating lunch keynote) from the field.

And the architectural boat tour on Saturday to top it all off was almost surreal. When we were all out on Lake Michigan and the fireworks went off over the magnificent skyline, I thought, “that’s how we roll :).” Plus, the docent from the Chicago Architecture Foundation was a font of information, and even long-time Chicagoans learned a lot along the way. If you weren’t there, you missed the best passive building party of the year, maybe ever. (But we’ll try to top it, promise.)

Finally, for the crew that just can’t get enough, the Passive Projects Tour on Sunday was, as always, an enormous hit. Tom Bassett-Dilley and Brandon Weiss put together an array of completed and in-progress projects that generated a buzz at every stop. Thanks to Tom and Brandon and to PHA-Chicago for all your help!

Cheers!

Kat